Towheeblog

A lot of us living creatures change our outer layers.  Dogs and horses shed as seasons change, new fur grows in.  Our species changes clothes.  Birds molt.  Old feathers wear and fade.  The sharpness and tightness of plumage is crucial for insulation, waterproofing and aerodynamic shape.  In spring it can be crucial for mating and nesting.

Right now some of our birds are starting to change from the utilitarian drab winter feathers into the bold, look-at-me coat needed for spring courtship. 
Here are a series of pictures of American Goldfinches in our Salem garden over a typical year.
These first two pictures show a goldfinch next to a siskin, the finch has its usual, bold white wing-bars but is just starting to lose the winter drab, in spots, for the spring bright, pale yellow. Took these shots yesterday, Jan. 9:

The next photo was taken in May, all goldfinches in fresh,  bright breeding plumage:

Here is one taken as the summer yellow and black is beginning to give way to autumn drab, August:

And here is a goldfinch in winter outfit, taken in early November:

When, how and how often a bird  molts varies by species, climate, habitat, protein supply (to form new feathers).  Most birds have to carefully and symmetrically molt wing feathers.  The gaps have to balance for the bird to keep flying straight.  Many ducks lose all their wing feathers at the same time, hide in a marsh and not fly again until all their new feathers grow in.

Nearly all the ducks we see now are in full breeding plumage, those that migrate out will have courted and formed pairs BEFORE they depart here. So males have to be in their brightest colors now. When shovelers and pintails first arrived last fall the males and females were hardly distinguishable.

Many young birds begin with kiddie plumage and the molt into adult appearance their first autumn.  Yet gulls and eagles may take four years to go from kindergarten outfits to grown-up.  A bald eagle with pure white head and pure white tail must be at least four years old.  A first year bald eagle is mostly dark brown with pale splotches on wings and chest.